Write-while-read access method for a memory device

ABSTRACT

A memory device includes a memory including first and second pages in first and second banks, respectively, an address decoder mapping command addresses to physical addresses. The memory device further includes circuitry configured to maintain a status indicating a most recently written page, decode received command sequences including command addresses and implementing an operation including (i) responsive to receiving a command sequence including a read command address that is pre-configured for reading data, causing the address decoder to map the read command address to one of the first and second pages selected according to the status, and (ii) responsive to receiving a second command sequence including a write command address that is pre-configured for writing data, causing the address decoder to map the write command address to one of the first and second pages selected according to the status.

PRIORITY APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 62/507,243 filed 17 May 2017; which application isincorporated herein by reference.

FIELD

The present technology relates to a memory device having a memory suchas NOR flash memory and embedded logic that, responsive to commandsequences, reads and writes data to the memory.

DESCRIPTION OF RELATED ART

Data processing systems are sometimes characterized as including a hostsystem and a memory system. The host system usually operates withlogical addresses that provide a layer of abstraction between the hostsystem software and physical memory in the memory system. The memorysystem can include a controller that performs logical to physicaladdress translations to translate the host level read and write requestsbased on the logical addresses into a command structure includingphysical or command addresses used by the memory device.

One type of memory that can be used in a memory system is a NOR flashmemory, which is often used to store code because of its superior randomaccess capability, as compared to a NAND flash memory. Reading(sequential) code requires that it be delivered in a proper sequence, soas to preserve the functionality of the code. When the code (or part ofit) stored on the NOR flash memory, for example, must be changed, thenthe possibility that it is being executed at the time must be addressed.

If the stored code is being executed at the same time a request isreceived to change the code, then the read operation for reading thecode needs to continue to some safe stopping place before it is replacedwith new code, so as not to cause an error in the execution of the code.The same is true for a write operation. The writing of the code must besafely completed or continue to some safe stopping place before the codecan be reliably read.

In conventional systems, the memory may be configured so that code, suchas boot code for example, is maintained at specified or default blocksin the memory. Using such a structure, a read of the boot code requiresaccess to the specified block, and use of the physical address dedicatedfor that specified block. A write of the boot code requires access tothe same specified block.

Executing a read command to read a page of data, for example, canrequire many clock cycles after the read command, as the data isdelivered one byte (or whatever unit) at a time to a memory interface.Likewise, executing a write command will require many clock cycles afterthe write command, as the data to be written are loaded onto the memory.This is programming operations (i.e., ease and write operations) arerelatively slow, meaning that they require many clock cycles. Thisstructure creates a bottleneck as the second one of the commands (theread command or the write command) must wait until the first one of thecommands (the other of the read command or the write command) has safelycompleted before execution.

In the scenario described above, the read operation is deliveringsequential code at the time that the write command is issued.Conventional memory systems can handle this situation by executing thewrite on a different bank (i.e., to a new address) and after writing thecode to the different bank, moving the sequential code to the specifiedor default bank, or perhaps instead of moving the sequential code thespecified or default bank, communicating the new address of thedifferent bank up the logical layers to be used for the next read of thesequential code. The moving of the sequential code after being writtento the different bank, would present a second possibility of conflict,and is not a robust solution. Likewise, changing the default address forthe sequential code to the new address can complicate system operation.Because of these complications, neither of these solutions is built intothe architecture of conventional memory.

Alternatively, the write operation can wait until a safe stopping placein the read operation (e.g., the end of a page read) and then overwritethe page. However, this would require a time consuming erase operationand then the write (programming) operation.

The technology disclosed provides a memory architecture that solvesthese problems.

SUMMARY

The present technology provides a memory device that is capable ofperforming a write-while-read operation that can, when a write operationis initiated, suspend and resume a reading operation without the need tocompletely restart the reading operation.

In one aspect of the present technology, a memory device is provided.The memory device described herein includes a memory, control circuitryand an address decoder. The memory is configured with pages, the pagesincluding a first set of pages including a first page in a first bankand a second page in a second bank. The address decoder maps receivedcommand addresses to physical addresses of pages and banks of thememory. The control circuitry is configured to maintain a statusindicating a most recently written page of the first set of pages, todecode received command sequences that comprise the command addresses,to execute operations identified in the command sequences, and toimplement an operation. The operation includes (i) responsive toreceiving a first command sequence including a read command address thatis pre-configured for reading data from the first set of pages, causingthe address decoder to map the read command address to one of the firstpage in the first bank and the second page in the second bank selectedin response to the status, and responsive to receiving a second commandsequence including a write command address that is pre-configured forwriting to the first set of pages, causing the address decoder to mapthe write command address to one of the first page in the first bank andthe second page in the second bank selected in response to the status.

In another aspect of the present technology, a method of operating amemory device is provided. The method includes configuring a first setof pages of the memory to include a first page in a first bank and asecond page in a second bank, mapping received command addresses tophysical addresses of the pages and the banks of the memory, maintaininga status indicating a most recently written page of the first set ofpages, decoding received command sequences that comprise the commandaddresses, executing operations identified in the command sequences, andimplementing an operation including: (i) responsive to receiving a firstcommand sequence including a read command address that is pre-configuredfor reading data from the first set of pages, mapping the read commandaddress to one of the first page in the first bank and the second pagein the second bank selected in response to the status; and (ii)responsive to receiving a second command sequence including a writecommand address that is pre-configured for writing to the first set ofpages, mapping the write command address to one of the first page in thefirst bank and the second page in the second bank selected in responseto the status.

In another aspect of the present technology, a method of manufacturing amemory device is provided. The method includes providing a memoryconfigured with pages, the pages including a first set of pagesincluding a first page in a first bank and a second page in a secondbank, providing and configuring an address decoder to map receivedcommand addresses to physical addresses of pages and banks of thememory; and providing control circuitry configured to maintain a statusindicating a most recently written page of the first set of pages, todecode received command sequences that comprise the command addresses,to execute operations identified in the command sequences, and toimplement an operation. The operation includes: (i) responsive toreceiving a first command sequence including a read command address thatis pre-configured for reading data from the first set of pages, causingthe address decoder to map the read command address to one of the firstpage in the first bank and the second page in the second bank selectedin response to the status; and (ii) responsive to receiving a secondcommand sequence including a write command address that ispre-configured for writing to the first set of pages, causing theaddress decoder to map the write command address to one of the firstpage in the first bank and the second page in the second bank selectedin response to the status.

Other aspects and advantages of the present technology can be seen onreview of the drawings, the detailed description and the claims, whichfollow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a functional block diagram of a system including ahost, a memory controller and a memory device configured to perform awrite-while-read operation.

FIG. 2 illustrates a functional block diagram of a memory device thatperforms a write-while-read operation.

FIG. 3 illustrates a functional block diagram of a remapping operationbeing performed after the write-while-read operation of FIG. 3 iscomplete.

FIG. 4 illustrates example mapping logic of mapping a command address toa physical address to a particular page of a set of pages of a memory.

FIG. 5 illustrates a flow chart including the various operations thatare performed in order to perform the write-while-read operation.

FIG. 6 is a simplified block diagram of an integrated circuit, forexample, a NOR flash memory device, including command logic and controlcircuits supporting a write-while-read operation and related operationsas described herein.

DETAILED DESCRIPTION

A detailed description of embodiments of the present technology isprovided with reference to the FIGS. 1-6.

The problems described in the background section of this disclosure canbe solved by providing a memory architecture that can configure, forexample, a boot block (or other blocks) to include sets of two or morebanks and pages to prevent address conflicts and prevent the need tomove written data and prevent the need to update read addresses foraccessing the code.

Specifically, the technology disclosed can overcome these problems byproviding a memory device that (i) configures a memory with a set ofpages that includes first and second pages in first and second banks,respectively, (ii) maps received command addresses to physical addressesof the pages and banks of the memory, and (iii) maintains a statusindicating a most recently written page of the set of pages. Thisstructure can allow the memory device to map a read command address thatis pre-configured for reading data from the set of pages to one of thefirst page in the first bank and the second page in the second bank,selected in response to the status and to map a write command addressthat is pre-configured for writing data from the set of pages in one ofthe first page in the first bank and the second page in the second bank,selected in response to the status.

FIG. 1 illustrates a functional block diagram of a system including ahost, a memory controller and a memory device configured to perform awrite-while-read operation. Specifically, FIG. 1 illustrates asimplified functional block diagram of a system 100, which comprises ahost 110, a communication bus 112, a memory controller 120, acommunication bus 122 and a memory device 130. In system 100 the host110 executes programs that read and write data using logical addresses.The host 110 communicates across the communication bus 112 to the memorycontroller 120 and the memory controller 120 communicates across thecommunication bus 122 to the memory device 130.

The host 110, for example, can be a computer system running an operatingsystem that delivers requests (e.g., write and read) to the memorycontroller 120 through the communication bus 112.

The communication bus 112 between the host 110 and the memory controller120 can be, for example, a peripheral component interconnect (PCI) bus,peripheral component interconnect express (PCIe) bus, serial ATA (SATA),and any other type of bus that communicates using appropriatecommunication protocols.

The memory controller 120 can be implemented using software or otherlogic structures in a microcontroller unit (MCU) or a dedicated memorycontroller chip. In other embodiments the host 110 and memory controller120 can be implemented on a single processor, or the host 110 and memorycontroller 120 can comprise parts of a complex data processing system.The memory controller 120 can acts as an interface between the host 110and the memory device 130. One function of the memory controller 120 isto translate higher-level read and write requests into the commandlanguage of the particular memory device 130 that can be used to accessphysical memory 139 included on the memory device 130. The memorycontroller 120 may include an interface layer (not illustrated) that isresponsible for composing command sequences for performing read andwrite operations to and from the memory device 130, in a manner that iscompatible with the memory device 130 and the physical memory 139. Thecommand sequences can be composed by translating logical addressesreceived from the host 110 into physical addresses for the memory device130.

The memory controller 120 is connected to the memory device 130 by thecommunication bus 122. For the purpose of this description, thecommunication bus 122 can be a communication system that transfers databetween nodes of the memory controller 120 and the memory device 130.The communication bus 122 can include bus lines (e.g., physical layerconnections like wires, optical fiber, wireless links, etc.), connectedto the memory controller 120 and the memory device 130.

For example, the memory controller 120 can use a bus structure having aplurality of bus lines I/O 0˜N, along with a chip select line (CSB)(active low or active high) and a clock line (CK). The communication bus122 can comprise a serial peripheral interface (SPI) bus or othersynchronous serial communication interface characterized by asynchronous clock line, a chip select line and one or more data linessynchronized with a synchronous clock on the synchronous clock line. SPIdevices typically use a four-wire synchronous serial communicationprotocol, which can communicate in full duplex mode (CK, CSB, masterin/slave out (MISO), master out/slave in (MOST)).

The memory device 130 includes a bus interface 132, control circuitry134, an address decoder 136, and physical memory 139. The physicalmemory 139 of the memory device can be a single-bit-per-cell ormultiple-bit-per-cell NOR non-volatile flash memory device or a set ofdevices such as solid state drive memory technologies. In otherexamples, the physical memory 139 can comprise other types ofnon-volatile memory devices, including single-bit-per-cell ormultiple-bit-per-cell NAND flash, phase change memory, magnetic memory,metal oxide programmable resistance memory and so on.

Further, portions of the physical memory 139 are configured with sets ofpages on which read and write operations are performed. For example, asillustrated in FIG. 1, the pages can include a first set of pages thatinclude a first page in a first bank of the physical memory 139 and asecond page in a second bank of the physical memory 139. Additionally,the first set of pages could include additional pages from the same ordifferent banks (not illustrated). The pages of the memory 139 caninclude a second set of pages that include a third page in a third bankof the physical memory 139 and a fourth page in a fourth bank of thephysical memory 139 (not illustrated). Alternatively, the third andfourth pages, of the second set of pages, can be respectively located inthe first and second banks of the physical memory 139. At least one ofthe pages of each set of pages must in a separate bank than the otherpage or pages of the set. These sets of pages can be configured ordesignated by logic on the memory device 130, such as a map or controlcircuitry.

The address decoder 136 of the memory device 130 includes a map 137 andstatus logic 138. The map 137 maps command addresses (e.g., read commandaddresses and write command addresses) received on the bus interface 132from the memory controller 120 to physical addresses of the pages andbanks of the physical memory 139. The status logic 138 is used toindicate to the map 137 which page of a set of pages is to be read fromand written to. In an implementation the map 137 can act as amultiplexer that responds to a status bit output by the status logic 138to determine which page of a set of pages is to be read from and whichpage of a set of pages is to be written to. The status logic 138 doesnot need to be located on the address decoder 136 and can be locatedsomewhere else on the memory device 130. This illustration of the memorydevice 130 is only for the purpose of showing the different elements ofand functions performed by the memory device 130.

The control circuitry 134 accesses the physical memory 139, executesmemory read and write operations and maintains a status that indicates amost recently written page of each of the sets of pages (i.e., the firstset of pages) of the physical memory 139. This status, which indicatesthe most recently written page, is what allows the map 137, by way ofthe status logic 138, to determine (map) which page of the set of pagesshould be written to, and allows the map 137, by way of the status logic138, to determine (map) which page of the set of pages should be readfrom.

The control circuitry 134 also decodes the command sequences received onthe bus interface 132 from the memory controller 120. These commandsequences can include corresponding operation codes, such as read,write, erase, etc., the command addresses and/or data, such as the datato be written to the physical memory 139. The control circuitry 134executes operations that are identified in the received commandsequences and also implements, at least in part, the write-while-readoperation.

For example, the write-while-read operation is performed when thecontrol circuitry 134 receives a first command sequence that includes aread command to read data (e.g., data X) and a read command address(that is pre-configured for reading data from the first set of pages)and then receives (before the read operation is complete) a secondcommand sequence that includes a write command to write/update the data(e.g., to update data X) and a write command address (that ispre-configured for writing data to the first set of pages). Thepre-configured read and write addresses can be set up using logic on thememory device 130. For example, the read command address that ispre-configured for reading data from a particular set of pages (e.g.,the first set of pages) is designated by the map 137 of the memorydevice 130 for reading the data. Similarly, the write command addressthat is pre-configured for writing data to the particular set of pages(e.g., the first set of pages) is also designated by the map 137 of thememory device 130. Alternatively, the memory controller 120 can beconfigured to assign (pre-configure) the read command addresses and thewrite command addresses to certain operations based, in part, on logiccontained thereon and/or based on a configuration or logic of theoperating system of the host 110.

This write-while-read operation can be performed because the readcommand address received from the memory controller 120 is mapped by theaddress decoder 136 to, for example, the first page of the first bank ofthe memory 139 and the (pre-configured) write command address receivedfrom the memory controller 120 is mapped by the address decoder 136 to,for example, the second page of the second bank of the memory 139. Forexample, a read operation of reading data X from the first page of thefirst bank of the physical memory 139 can be paused/suspended while thewrite command proceeds to write updated data X to the second page of thesecond bank of the physical memory 139. Once the writing operation ispartially complete (e.g., at a point where the read operation canresume) or is fully complete, the read operation of reading data X fromthe first page of the first bank of the physical memory 139 can resumefrom where it left off, without needing to restart from the beginning.After the writing is complete, the updated data X is stored the secondpage of the second bank of the physical memory 139.

This write-while-read operation requires the data to be read/writtenfrom/to different banks of the physical memory 139. Without the readingand the writing being directed to different banks of the physical memory139, the reading would have to start from the beginning because, forexample, the write operation would erase the entire bank of the physicalmemory 139. This write-while-read operation also requires, after thereading of data X is complete, the memory device 130 to update thestatus that indicates the most recently written page of the set ofpages. This will cause the read command address to be mapped to thepage/bank that contains the updated data X and cause the write commandto be mapped to the page/bank that was previously read from. In otherwords, the combination of the address decoder 136 and the status allowsthe control circuitry 134 to implement the operation that switches thepages/banks that are mapped to the read command addresses and the writecommand addresses. In this example, after the mapping is updated theread command will be mapped to the second page of the second bank of thephysical memory 139 and the write command will be mapped to the firstpage of the first bank of the physical memory 139. The map 137 and thestatus logic 138 of the address decoder 136 in combination with thecontrol circuitry 134 are able to manage the mapping for more than justone set of pages.

FIG. 2 illustrates a functional block diagram of a memory device thatperforms a write-while-read operation. Specifically, FIG. 2 illustratesa memory device 200 that includes control circuitry 210, an addressdecoder 220 having status logic 222 and a map 224, and physical memory.The physical memory can include a physical bank0 225 including page A226 and a physical bank1 227 including page B 228. The operation of thememory device 200 of FIG. 2 is similar to that of the memory device 130system 100 of FIG. 1. Therefore, some redundant descriptions thereof areomitted.

The address decoder 220 of the memory device 200 performs the mappingbetween the read/write command addresses and the physical addresses ofthe memory based on the status logic 222. Further, as illustrated byFIG. 2, command sequences for performing read and write operations arereceived from a memory controller (not illustrated). A representativepath for the read operation is represented by a solid line, arepresentative path for the write operation is represented by a dashedline and representative paths for the mapping performed by the map 224of the address decoder 220 are represented by dotted lines.

As mentioned above, the physical memory of the memory device 200 caninclude a physical bank0 225 that includes physical page A 226 andinclude physical bank1 227 that includes physical page B 228. Physicalpage A 226 and physical page B 228 can be a set of pages. Unlike thelogical addresses that are referenced by a host (not illustrated) or bysoftware running on the host, these banks and pages are physical bankslocated on the memory of the memory device 200 and they have physicaladdresses.

The control circuitry 210 of the memory device 200 can decode thereceived command sequences that include operation codes, such as read,write, erase, etc., command addresses, data, as well as otherinformation, as received from a memory controller. Specifically, thereceived command sequences can include a read command address that ispre-configured by the map 224 of the address decoder 220 for readingdata from a specific set of pages of the physical memory and can includea write command address that is pre-configured by the map 224 of theaddress decoder 220 for writing data to the specific set of pages of thephysical memory. The decoded commands and command addresses are receivedby the address decoder 220. The control circuitry 210 can also maintaina status of which page of the set of pages of the physical memory hasbeen most recently written to. The map 224 of the address decoder 220can map (dotted lines) the (pre-configured) read command address to theappropriate page of the set of pages of the memory device 200. The map224 can also map the (pre-configured) write command address to theappropriate page of the set of pages of the memory device 200.

Specifically, the map 224 and the status logic 222 of the addressdecoder 220 can be implemented to map the (pre-configured) read commandaddress to the appropriate page of the set of pages (e.g., page A 226and page B 228). The map 224 and the status logic 222 can also beimplemented to map the (pre-configured) write command address to theappropriate page of the set of pages (e.g., page A 226 and page B 228).The map 224 of the address decoder 220 can be a simple table orsomething more complex. Further, the map 224 can be implemented so thatit only maps addresses that are pre-configured for reading/writingto/from the sets of pages that are for implementing a write-while-readoperation. The status logic 222 indicates to the map 224 which physicaladdress (e.g., which of two different physical address) should beselected for a read operation and which physical address should beselected for a write operation. This indication by the status logic 222to the map 224 is based on the status that is maintained by the controlcircuitry 210 and indicates which of the pages of the set of pages hasbeen most recently written to.

In the implementation illustrated in FIG. 2, the map 224 of the addressdecoder 220 provides a translation (mapping) between (i) the readcommand address that is pre-configured for reading data from a set ofpages of the physical memory (the read command address is included inthe command sequence received from the memory controller) and (ii)physical addresses of page A 226 of physical bank0 225 and page B 228 ofphysical bank1 227. Similarly, the map 224 of the address decoder 220provides a translation (mapping) between (i) the write command addressesthat is pre-configured for writing data to a set of pages of thephysical memory (the write command address is included in the commandsequence received from the memory controller) and (ii) physicaladdresses of page A 226 of physical bank0 225 and page B 228 of physicalbank1 227.

As mentioned above, page A 226 and page B 228 are configured as a set ofpages (from different banks). In this implementation, the map 224 of theaddress decoder 220 is capable of mapping the (pre-configured) readcommand address to both pages (i.e., page A 226 and page B 228) of theset of pages, and is capable of mapping the (pre-configured) writecommand address to both pages of the set of pages. The dotted lines inthe map 224 illustrate that the map 224 is capable of mapping the(pre-configured) read command address, as well as the (pre-configured)write command address to both of page A 226 and page B 228. The statuslogic 222 of the address decoder 220 is able to, based on the status ofthe pages of the set of pages, control which page of the set of pagesshould be read from and which page of the set of pages is to be writtento based on the status that is maintained by, for example, the controlcircuitry 210 of the address decoder 220. In an implementation, thestatus logic 222 can act as a register (a status register, a flagregister, a condition register, etc.) that toggles a bit based on whichpage of the set of pages has been most recently written to. The bit canbe toggled by the control circuitry 210 that maintains the status or thebit can be toggled by some other mechanism. Note that the status logic222 can perform this same function for more than just one set of pages.Based on the status provided by the status logic 222, the map 224 canact as a switch that has an input for the (pre-configured) read commandaddress and can select one of the physical address of page A 226 and thephysical address of page B 228. The same concept is applied to the(pre-configured) write command address.

For example, if the status indicates that page A 226 was the mostrecently written page of the set of pages, then the status provided bythe status logic 222 would select (or cause the map 224 to select) pageA 226 (see path “A” which leads to page A 226) for performing a readoperation. Alternatively, if the status indicates that page B 228 wasthe most recently written page of the set of pages, then the statuslogic 222 would select (or cause the map 224 to select) page B 228 (seepath “B” which leads to page B 228) for performing the read operation.The same concept applies to writing operations. For example, if thestatus indicates that page A 226 was the most recently written page ofthe set of pages, then the status provided by the status logic 222 wouldselect (or cause the map 224 to select) page B 226 (see path “B” whichleads to page B 226) for performing a write operation. Alternatively, ifthe status indicates that page B 228 was the most recently written pageof the set of pages, then the status logic 222 would select (or causethe map 224 to select) page A 228 (see path “A” which leads to page A228) for performing the write operation.

Additionally, the control circuitry 210 can also keep the addressdecoder 220 updated so that the correct pages of the sets of pages(e.g., page A 226 and page B 228) are identified for read and writeoperations. For example, the control circuitry 210 can update the map224 to add or change which command addresses are pre-configured forreading data and writing data and to add or change which pages of theset of pages of the memory are actually mapped to the pre-configuredcommand addresses.

When the read operation is mapped to, for example, page A 226, the readoperation will proceed to read the data from page A 226 back through thememory controller and eventually to the host and the software running onthe host. Various timing, buffering and caching mechanisms (notillustrated) are typically implemented to assist in the transmission ofthe read request to the memory device 200 and the transmission of theread data from the memory device 200, through the controller, andultimately to the host (operating system). Those skilled in the art willunderstand the various timing, buffering and caching mechanismsnecessary to complete this read operation.

Referring to FIG. 2, an example of a read operation that reads “code x”from the page A 226 of the memory device 200 and an example of a writeoperation that writes “updated code x” to page B 228 of the memorydevice 200 are provided. Specifically, FIG. 2 illustrates that a commandsequence to read “code x” has been received from the host/controller,and that a command sequence to update “code x” has been received fromthe host/controller before the reading of “code x” has completed. Asdescribed in the background section of this application, manyconventional memory systems would be forced to stop the read operation,allow the write operation to start and then finish, and then restart theread operation from the beginning. However, because of the uniquestructure provided by this write-while-read technology the writeoperation that updates “code x” can be performed without the need tostop and then restart the operation of reading “code x.” This can beachieved because the (pre-configured) read command address is mapped bythe address decoder 220 to a different page in a different physical bankthan the (pre-configured) write command address. Accordingly, the “new”or “updated” version of code x can be written without necessitating astop and then restart of the reading of the “old” or “original” versionof “code x.” After a portion of the writing operation is complete orafter the entire writing operation is complete, the suspended readingoperation can resume from exactly where it left off.

In a different implementation, the memory device 200 can supportparallel or simultaneous data transfer using dedicated busses. Thiswould allow the read operation to continue without interruption (e.g.,without suspending and then resuming the read operation) while the writeoperation is performed.

As illustrated in FIG. 2, this write-while-read operation can beperformed because the control circuitry 210 maintains the statusindicating a most recently written page of the set of pages (e.g., pageA 226 and page B 228). During the operation illustrated in FIG. 2 (andbefore the completion of the writing operation to write the updated codex to page B 228), the status indicates that page A 226 was the mostrecently written page of the set of pages. Accordingly, the status logic222, based on the status maintained by the control circuitry 210, causesthe map 224 to map the (pre-configured) read command address to page A226 (see path A of the read operation, and see where the potential pathfor reading from page B 228 is not selected (the path is “XX”ed out)).Further, based on the status maintained by the control circuitry 210,the status logic 222 causes the map 224 to map the subsequent(pre-configured) write command address to page B 228 (see path B of thewrite operation, and see where the potential path for writing to page A226 is not selected (the path is “XX”ed out)). As a result, the controlcircuitry 210, upon receiving a first command sequence that includes theread command and the (pre-configured) read command address to read thedata (i.e., code x) from the set of pages, the address decoder 220 iscaused to map the (pre-configured) read command address to page A 226.This is accomplished because the status logic 222 causes the map 224 toselect path A based on the status maintained by the control circuitry210 of the memory device 200.

Furthermore, the control circuitry 210, upon receiving a second commandsequence that includes the write command and the (pre-configured) writecommand address to write the data (i.e., updated code x) to the set ofpages, the address decoder 220 is caused to map the (pre-configured)write command address to page B 228. Again, this is accomplished becauseof the status logic 222 causes the map 224 to select path B based on thestatus maintained by the control circuitry 210 of the memory device 200.

The write-while-read operation can proceed in such a manner that thesuspended read operation can resume while, for example, the writeoperation is erasing physical bank1 227. Then, after physical bank1 227is erased, the read operation can then again be suspended in order forthe writing operation to proceed. Once a portion of or the entirewriting operation is complete, the read operation can then resume again.

After “code x” has been read from page A 226 (i.e., after the readoperation is complete) and “updated code x” resides on page B 228, thepresent technology must do some “remapping” so that the next time arequest to read “code x” is issued, the “updated code x” is read ratherthan the older version of “code x.” This “remapping” is essentiallyperformed by updating the status, which will cause the next read commandto read “code x” to be mapped to page B 228, of the set of pages. Inother words, page B 228 is identified by the status as being the mostrecent page of the set of pages that has been written to. This isdescribed in further detail with reference to FIG. 3.

FIG. 3 illustrates a functional block diagram of a remapping operationbeing performed after the write-while-read operation of FIG. 3 iscomplete. FIG. 3 illustrates the same memory device 200 of FIG. 2.However, FIG. 3 is different from FIG. 2 because the status has beenupdated by the control circuitry 210, so that the map 224 maps the(pre-configured) read command address to the physical address of page B228, to which (in FIG. 2) the “updated code x” has been written. Now,the next time a read request to read “code x” is issued, the readoperation will be translated to the physical address of physical page B228. As described above, the control circuitry 210 of the memory device200 manages the status indicating the most recently written page of theset of pages. However, any other part of the memory device 200 canmanage the status. The memory device 200 itself, or the memorycontroller (not illustrated), or the host (not illustrated) may store acopy of the map 224 and/or a copy of the status indicating which of thepages of the set of pages was most recently written to. These copies canbe used to recover from corruption or recent power loss causing theoriginal map 224 and/or status to be compromised.

It has been described that the address decoder 220 (e.g., the map 224and/or the status logic 222) and/or the status are only updated afterboth the read and write operations are complete. However, the technologydisclosed may update the address decoder 220 and/or the status after thewrite operation has finished, but while the read operation continues.Additional logic on the memory controller and/or the memory device 200will be necessary to allow the remapping to be done before the readoperation is finished in order allow original “code x” to continue to beread from page B 228 in the implementation illustrated in FIG. 3.

FIG. 3 also illustrates that the control circuitry 210 of the memorydevice 20 updates the status logic 222 and/or the map 224 to map the(pre-configured) write command address to the other page of the set ofpages (i.e., page A 226). Without this additional remapping of the writecommand address, both the (pre-configured) write command address and the(pre-configured) read command address would be mapped to the physicaladdress of physical page B 228. FIG. 3 illustrates that the(pre-configured) write command address is mapped to the physical addressof physical page A 226, because, based on the status, the status logic222 causes the map 224 to select page A 226. In other words, the statuslogic 222 causes the map 224 to switch or ping-pong between page A 226and page B 228 as they are mapped to the (pre-configured) read and writecommand addresses. This switching or ping-ponging is one way to performthe write-while-read operation, such that the memory device 200 does notneed to implement any additional logic once the set of pages (i.e.,pages A and B) is determined to correspond to the (pre-configured)command addresses. As mentioned above, the logic required to accomplishthis ping-ponging can typically be achieved by implementing the statuslogic 222 to simply change one bit in an address that allows the map 224to select which of the physical banks are addressed.

However, the (pre-configured) read and write command addresses do notnecessarily need to be mapped according to this ping-pong technique. Adifferent page of the physical bank0 225 and/or a different page of thephysical bank1 227 could be used. Additional/different physical bankscould be used as well. Also, rather than using two pages, there might bethree pages in the set of pages from different banks grouped together,and the write-while-read operation could just continuously rotatethrough the three pages. In order to accomplish this, the status logic222 could, for example, use more than one bit to indicate which of thethree pages in the set of pages was most recently written to and whichof the three pages was most recently ready from. Departure from thisping-pong technique requires additional logic to be executed by thememory device 200.

An example implementation of the write-while-read operation illustratedin FIGS. 2 and 3 is the data that is read and the data that is written(or updated) is dedicated random-access code, such as boot code. Usingthis structure described, the updated boot code can always be read oraccessed using the (pre-configured) read command address and the bootcode can always be further updated by performing a write using the(pre-configured) write command address, which will be mapped to aphysical page of a different physical block that is being accessed bythe read operation. It is possible that the boot code or other data thatis the subject to the write-while-read operation occupies more than asingle physical page of a physical memory bank. This is not typical ofboot code but it is possible, and it is certainly possible with othertypes of data. However, the write-while-read operation can continue inthe same manner if more than one page of physical memory is necessary.For example, subsequent logical addresses can be designated as beingonly for reading and can be mapped to physical pages in the same manneras discussed above with reference to FIGS. 2 and 3. The same conceptapplies to the write operation.

The memory device 200 can also manage multiple sets of pages. Forexample, a second set of pages could occupy physical bank0 225 andphysical bank1 227. Using the examples from above, this second set ofpages could be used for “code y” and “updated code y.” Furthermore, thesecond set of pages could be from other physical banks, such as physicalbank 2 (not illustrated) and physical bank 3 (not illustrated). Thistechnology can implement many more sets of pages and is only limited onthe amount of physical memory reserved for such operations. With theadditional sets of pages, the control circuitry 210 of the memory device200 will need to store and maintain a separate status of the mostrecently written page of each of the sets of pages.

FIG. 4 illustrates example mapping logic of mapping a command address toa physical address of a particular page of a set of pages of a memory.Specifically, FIG. 4 illustrates mapping logic 400 before remapping(e.g., the operation illustrated in FIG. 2) and illustrates mappinglogic 410 after the remapping is performed (e.g., the operationillustrated in FIG. 3). Similar to the example discussed with referenceto FIG. 2, mapping logic 400 maps the (pre-configured) read commandaddress to the physical address of physical page A because the statusindicates that page A is the most recent page, of the set, that has beenwritten to. Mapping logic 400 also maps the (pre-configured) writecommand address to the physical address of physical page B, because thestatus indicates that page A is the most recent page, of the set, thathas been written to (and that page B, of the set, is not the most recentpage that has been written to).

Similar to the example discussed with reference to FIG. 3, mapping logic410 illustrates that after the remapping process performed, the(pre-configured) read command address is now mapped to the physicaladdress of physical page B, because the status indicates that page B isthe most recent page, of the set, that has been written to. Mappinglogic 410 also illustrates that the write command address is now mappedto the physical address of physical page A, because the status indicatesthat page B is the most recent page, of the set, that has been writtento (and that page A, of the set, is not the most recent page that hasbeen written to).

In the mapping logic 400 and 410 illustrated in FIG. 4, the solid lineillustrates a read operation that points to the (pre-configured) readcommand address and the dashed line illustrates a write operation thatpoints to the (pre-configured) write command address. Mapping logic 400illustrates that the read operation utilizes page A (not the grayed outpage B) because page A was the most recent page that was written to.Similarly, mapping logic 400 illustrates that the write operationutilizes page B (not the grayed out page A) because page B was not themost recent page that was written to. In contrast, mapping logic 410illustrates that the read operation utilizes page B (not the grayed outpage A) because page B was the most recent page that was written to.Similarly, mapping logic 410 illustrates that the write operationutilizes page A (not the grayed out page B) because page A was not themost recent page that was written to.

While FIG. 4 illustrates high level diagrams, in the sense that actuallogical and physical addresses are not included in the mapping logic 400and 410, it is to be understood by a person of ordinary skill in the artthat the proper syntax for referring to specific logical and physicaladdresses will be required for the mapping logic to be implemented bythe memory system that is implementing the write-while-read operations.The specific addressing syntaxes can be dictated by the type of memorysystem that is being implemented.

FIG. 5 illustrates a flow chart including the various operations thatare performed in order to perform the write-while-read operation.Specifically, a flow chart 500 of FIG. 5 illustrates the operationsperformed by the memory device in order to implement thewrite-while-read operation.

In operation 505 the system is initialized (e.g., setup for reading andwriting operations to be performed). For example, in operation 505 thememory is configured with a set or sets of pages. A first set of pagescan include a first page in a first bank of the memory and a second pagein a second bank of the memory. Further, in operation 505 the controlcircuitry is configured to maintain the status that indicates the mostrecently written page of the set of pages. The address decoder isconfigured to map the command addresses to physical addresses of pagesand banks of the memory using a map and status logic. Additionally,command logic of the memory device is configured to decode the commandsequences received on a bus interface, where the command sequencesinclude one or more of corresponding operation codes, command addressesand data. The command logic is also configured to enable the controlcircuitry to execute the operations identified in the received commandsequences and to implement the write-while read operation.

Once the system is initialized, in operation 510 a first commandsequence is received and decoded. The first command sequence includes aread command and a read command address for reading data from the set ofpages.

In operation 515 the address decoder maps a (pre-configured) readcommand address to one of the first page in the first bank and thesecond page in the second bank, selected in response to the status. Forexample, if the first page of the first bank were identified by thestatus as being the page what was most recently written to (i.e., thepage having the most recently updated version of the data), then thefirst page of the first bank is selected and mapped to the first page inthe first bank by the address decoder.

In operation 520 the data is read from the one of the first page and thesecond page that is mapped to the (pre-configured) read command address.

In operation 525 a second command sequence including a write command(i.e., a write operation) to write data to a (pre-configured) writecommand address is received. Upon receiving the second command sequence,a determination is made in operation 530 as to whether the reading ofthe data, as begun in operation 520, has completed. If it is determinedin operation 530 the read operation is finished, then a write operation535 proceeds as normal, meaning that the memory device will not need tosuspend the reading operation in order to perform the writing operation.In other words, the memory device will not need to perform awrite-while-read operation. However, the write operation to write thedata to the (pre-configured) write command address is still performedusing to the maintained status and mapping of the address decoder.

If a determination is made in operation 530 that the reading of the datais not complete, then in operation 540 the reading operation will besuspended and the writing operation will begin. Just as in operation535, the data will be written to the other of the first and secondpages, based on the maintained status. Specifically, the address decoderis caused to map the (pre-configured) write command address included inthe second command sequence to one of the first page in the first bankand the second page in the second bank, selected in response to thestatus. For example, if the first page were the page that was being readfrom, then the second page would be selected and mapped to the(pre-configured) write command address because of the page indicated bythe status.

As mentioned above, in order to allow a writing operation to proceed, inoperation 540 the read operation is suspended and the data is written tothe one of the first page and the second page that is mapped to the(pre-configured) write command address by the address decoder map. Thewriting operation can have many stages, such as erasing the memory bank,loading a write buffer, etc. The reading can resume (from suspension)while the memory device is performing some of these stages or betweensome of these stages. For example, while the memory bank is being erasedthe reading can resume in operation 545. Then after the erasing stage iscomplete, the writing operation will continue and the reading operationwill be suspended again. Accordingly, operations 540 and 545 may caniterate several times until both the reading and the writing are fullycomplete.

As discussed in this disclosure, a feature of this technology is thatthe reading is not restarted from the beginning. Rather, it is resumedfrom where it left off. This can be achieved because the page that wasbeing read from is from a different physical bank than the page that wasbeing written to.

After the writing is completed in operation 535 and also after thereading is completed in operation 545, operation 550 is performed. Inoperation 550 the status is updated to reflect the most recently writtenpage of the first and second pages and the address decoder and/or theupdated to operate accordingly. In operation 555 the procedure ends.

These operations illustrated in flow chart 500 are merely examples ofimplementing the technology disclosed. These operations can be performedin different orders and some of these operations may not be necessaryand/or may be replaced by other operations described in this document.

FIG. 6 is a simplified block diagram of an integrated circuit 600, forexample, a NOR flash memory device, including command logic and controlcircuits supporting the write-while-read and related operations asdescribed herein. The integrated circuit 600 can be implemented on asingle chip. For example, some or all of the components (and theoperations performed thereby) of the memory device 200 of FIGS. 2 and 3can be included in the integrated circuit 600. Alternatively, some ofthe components (and the operations performed thereby) of the memorycontroller 120 of FIG. 1 can be included in the integrated circuit 600.

I/O block 602 shows a synchronous serial interface compliant with aserial peripheral interface SPI standard, and having standard pins. CS#is chip select, which can correspond to the CSB line discussed above.When CS# is brought low the device is selected. The RESET# signal allowsthe device to be reset, terminating the currently running process andresetting the state machine. GND and VDD are ground and power supply,respectively. In standard SPI, SI and SO are serial data input andoutput, respectively. In Dual SPI operation, SI and SO becomebidirectional I/O pins: SIO0 and SIO1. In Quad SPI operation, SIO2 andSIO3 are available for higher-speed transfer. This is an example only;many pin configurations are possible. Serial clock SLCK 604 (or just CK604) is also provided. A clock generator 605 on the integrated circuitgenerates clock signals for the command logic 620 and other elements ofthe integrated circuit. In this embodiment the clock generator 605receives the SCLK from the SLCK 604 pin. The bus interface representedby I/O block 602 can support double data rate (DDR) or single data rate(SDR) protocols.

Other types of serial interfaces can be used in various embodiments.Memory technologies other than NOR flash memory may be used.

A control signal used to indicate the beginning and ending of a commandsequence described herein may be signals on one or more of the bus linesin the block 602 in some examples. For example, in some embodiments, CS#or RESET# may be toggled, such as being pulled low-to-high in a firsttransition or high-to-low in a second transition. Alternatively, or inaddition, a termination event may be generated internally by the chipcontrol logic.

Status indicator 608 includes circuitry and logic configured to maintaina status indicating a most recently written page of dedicated sets ofpages of the NOR flash memory array 628. For example, the NOR flashmemory array 628 can be configured with sets of pages, such as a firstset of pages including a first page in a first bank and a second page ina second bank. Additional sets of pages can also be configured. For thisexample only a first set of pages will be discussed. This structureregarding the sets of pages and the status has been described in detailwith reference to FIGS. 1-4.

The status indicator 608 can contain logic that is able to indicatewhich pages, of the sets of pages of the NOR flash memory array 628,have been most recently written to. For example, the status maintainedby the status indicator 608 can indicate a most recently written page ofthe first set of pages. If there are additional sets of pages, asmentioned above, the status indicator 608 will also keep track of whichpages of the other sets of pages have been most recently written to. Thestatus indicator 608 can obtain these physical addresses of the mostrecently written pages from the address generator 606 or from othercomponents of the integrated circuit 600. As discussed with reference toFIGS. 2 and 3, functions of the status logic 222 can be implemented bythe status indicator 608.

A write-while-read (WWR) set mapping decoder 606A performs theoperations of, for example, the address decoder 220 including the map224 and the status logic 222, as described with reference to FIGS. 2 and3. Specifically, the WWR set mapping decoder 606A implements logic basedon the status provided by the status indicator 608 and mapspre-configured command addresses to physical addresses of pages andbanks of the physical memory, such as the NOR flash memory array 628,accordingly. The WWR set mapping decoder 606A can map the(pre-configured) read command addresses and the (pre-configured) writecommand addresses to the physical addresses of pages and banks of thephysical memory based on a map, such as the map 224 of FIGS. 2 and 3,and based logic, such as the status logic 222 of FIGS. 2 and 3. Thebanks (bank 0 and bank 1) of the NOR flash memory array 628 can bemapped by the logic of the WWR set mapping decoder 606A by simplychanging a bit in the address. For example, to enable writing to a pageof bank 1 rather than a page of bank 0, the decoder 606A can change onebit of the page address. Based on a command sequence received from thestate machine 622 (or other components of the integrated circuit 600)and the status obtained from the status indicator 608 the WWR setmapping decoder 606A will map the (pre-configured) read command addressfor reading data from the set of pages of the NOR flash memory array 628to one of the first page in the first bank and the second page in thesecond bank. For the read command, the most recently written page of theset of pages will be read from based on the status indicated by thestatus indicator 608 and the combination of the status logic and the mapof the WWR set mapping decoder 606A. This will ensure that the mostrecent version of the data is read from the appropriate page. Likewise,the WWR set mapping decoder 606A will map the write command addresspre-configured for writing the data to one of the first page in thefirst bank and the second page in the second bank. The (pre-configured)write command will typically be mapped, based on the status obtainedfrom the status indicator 608, to the page of the set of pages that hasnot most recently been written from.

The WWR set mapping decoder 606A, combined with other circuitry andlogic of the integrated circuit 600, performs the write-while-readoperations described with reference to FIGS. 1-5. Some redundantdescriptions thereof are omitted. However, it is noted that the statusindicator 608 is continuously updated based on which page, of aparticular set of pages, has been most recently written to. Bycontinuously updating the status indicator 608, the integrated circuit600 is able to ping-pong the reading and the writing from and to theappropriate pages of the sets of pages. As mentioned above, dependingupon the implementation this can be done by simply changing a bit of thebank address that is being accessed. This mechanism allows the mostrecently written data (from the set of pages) to always be read andfurther allows data to be written to another page of the set of pageswithout the need to stop and then restart the read operation.

Address generator 606 includes circuits to provide the physical addresssequences for access to the NOR flash memory array 628.

Data register 614 can act as an input buffer to store portions ofcommand sequences in some embodiments. Data and parameters may be storedin SRAM buffer 624 in support of interruptible write operations, andother operations. In some examples, the data register 614 may be part ofthe SRAM buffer 624.

Integrated circuit 600 also includes command logic 620, which maygenerate internal control signals, and control circuitry such as a statemachine 622 with supporting bias circuits. High-voltage generator 626generates any higher voltages required, for example for read, program,and erase operations. The command logic 620 executes command proceduresindicating read, write, erase and data associated therewith. The controlcircuitry including the state machine 622, in this example, executesembedded program, erase and read operations which access the memoryarray 628 when enabled by the command logic.

Memory array 628 includes, in addition to the WWR set mapping decoder606A, X-decoder 606B and Y-decoder 632, and data signals are output viasense amplifier 634. Output buffer 636 may hold output data for outputfrom the device.

In the example shown in FIG. 6, a command sequence comprises a sequenceof bytes received on the SIO pins in the I/O block 602. The commandlogic 620 can include logic to decode the operation code, route thestart address to the address counter, and provide control signals to setup and initiate embedded processes identified in the command sequences,including write (e.g. program and erase) and read processes using thestate machine 622. The example shown in FIG. 6 is a serial flash deviceusing a serial bus interface for sequential data access. The serial businterface includes at least one synchronous clock signal CK, datasignals, where the width of the storage unit carrying the data isgreater than or equal to one bit, and at least one chip select signalCSB. Using a serial bus interface, the command sequences described abovecan be supported.

This configuration can be used to support buses compliant with theserial peripheral interface SPI standard bus architecture, where theport CS corresponds with the SPI active low chip select CSB, the port CKcorresponds with the SPI serial clock SCLK; the port 0 corresponds withthe SPI master-out/slave-in MOSI port, the port 1 corresponds with theSPI first master-in/slave-out MISO1 port; the port 2 corresponds withthe SPI second master-in/slave-out MISO2 port; and the port 8corresponds with the SPI third master-in/slave-out MISO3 port. Thetechnology described herein can be used with other standard andnon-standard bus architectures, including for example I2C.

Those skilled in the art will appreciate that this diagram is providedfor example of one embodiment only; a device supporting interruptiblewrite command sequences as described herein may vary widely from thisdiagram, comprising different elements, connected in different ways.

The embodiment shown in FIG. 6 includes a NOR flash memory array. Othertypes of memory systems can be utilized as well, including nonvolatilememory types including phase change memory PCM, resistive memory elementmemory known as ReRAM or RRAM, NAND flash memory, magnetoresistivememory, and so on. Also, other types of memory systems can be utilizedthat may include volatile memory such as DRAM.

A number of flowcharts illustrating logic executed by a memorycontroller or by memory device are described herein. The logic can beimplemented using processors programmed using computer programs storedin memory accessible to the computer systems and executable by theprocessors, by dedicated logic hardware, including field programmableintegrated circuits, state machines implemented in circuitry and bycombinations of dedicated logic hardware and computer programs. With allflowcharts herein, it will be appreciated that many of the steps can becombined, performed in parallel, or performed in a different sequencewithout affecting the functions achieved. In some cases, as the readerwill appreciate, a rearrangement of steps will achieve the same resultsonly if certain other changes are made as well. In other cases, as thereader will appreciate, a rearrangement of steps will achieve the sameresults only if certain conditions are satisfied. Furthermore, it willbe appreciated that the flow charts herein show only steps that arepertinent to an understanding of the invention, and it will beunderstood that numerous additional steps for accomplishing otherfunctions can be performed before, after and between those shown.

While the present invention is disclosed by reference to the preferredembodiments and examples detailed above, it is to be understood thatthese examples are intended in an illustrative rather than in a limitingsense. It is contemplated that modifications and combinations willreadily occur to those skilled in the art, which modifications andcombinations will be within the spirit of the invention and the scope ofthe following claims.

What is claimed is:
 1. A memory device, comprising: a memory configuredwith pages, the pages including a first set of pages including a firstpage in a first bank and a second page in a second bank; an addressdecoder that maps received command addresses to physical addresses ofpages and banks of the memory; and control circuitry configured tomaintain a status indicating a most recently written page of the firstset of pages, to decode received command sequences that comprise thecommand addresses, to execute operations identified in the commandsequences, and to implement an operation including: responsive toreceiving a first command sequence including a read command address thatis pre-configured for reading data from the first set of pages, (i)selecting one of the first page in the first bank and the second page inthe second bank in response to the maintained status and (ii) causingthe address decoder to map the read command address to the selected oneof the first page in the first bank and the second page in the secondbank; and responsive to receiving a second command sequence including awrite command address that is pre-configured for writing to the firstset of pages, (i) selecting one of the first page in the first bank andthe second page in the second bank in response to the maintained statusand (ii) causing the address decoder to map the write command address tothe selected one of the first page in the first bank and the second pagein the second bank.
 2. The memory device of claim 1, wherein theoperation further includes: responsive to receiving the first commandsequence, reading the data from the one of the first page and the secondpage, of the first set of pages, selected in response to the status; andresponsive to receiving the second command sequence during the readingof the data, writing data to the one of the first page and the secondpage, of the first set of pages, selected in response to the status. 3.The memory device of claim 2, wherein the selected one of the first pageand the second page, from which the data is read, is one of the firstpage and the second page indicated by the status as being the mostrecently written page.
 4. The memory device of claim 3, wherein theselected one of the first page and the second page, to which the data iswritten, is one of the first page and the second page that is notindicated by the status as being the most recently written page.
 5. Thememory device of claim 2, wherein the reading of the data includesreading boot code from the one of the first page and the second pageselected in response to the status and the writing of the data includeswriting boot code to the one of the first page and the second pageselected in response to the status.
 6. The memory device of claim 2,wherein the operation further includes, after completion of the writing,updating the status to indicate the one of the first page and the secondpage, to which the data was written, as the most recently written pageof the first set of pages.
 7. The memory device of claim 2, wherein theoperation further includes: resuming the reading after receiving thesecond command sequence; and after completion of the reading and thewriting, updating the status to indicate the one of the first page andthe second page, to which the data was written, as the most recentlywritten page of the first set of pages.
 8. The memory device of claim 2,wherein, when the second command sequence is received before the readingof the data is complete, the operation: suspends the reading of the datafrom a selected one of the first set of pages selected for the read;begins the writing of the data to the other page of the first set ofpages; and prior to completion of the writing of the data, resumes thereading of the data from the selected one of the first set of pagesselected for the read.
 9. The memory device of claim 2, wherein, whenthe second command sequence is received before the reading of the datais complete, the operation: suspends the reading of the data from aselected one of the first set of pages selected for the read; begins thewriting of the data to the other page of the first set of pages; andafter completion of the writing of the data, resumes the reading of thedata from the selected one of the first set of pages selected for theread.
 10. The memory device of claim 1, wherein the pages include asecond set of pages, the second set of pages including a third page in athird bank and a fourth page in a fourth bank, and wherein themaintained status further indicates a most recently written page of thesecond set of pages.
 11. The memory device of claim 10, wherein theoperation further includes: responsive to receiving a third commandsequence, reading the data from the one of the third page and the fourthpage, of the second set of pages, selected in response to the status;and responsive to receiving a fourth command sequence, writing data fromthe one of the third page and the fourth page, of the second set ofpages, selected in response to the status.
 12. The memory device ofclaim 1, wherein the pages include a second set of pages, the second setof pages including a third page in the first bank and a fourth page inthe second bank, and wherein maintained status further indicates a mostrecently written page of the second set of pages.
 13. The memory deviceof claim 12, wherein the operation further includes: responsive toreceiving a third command sequence, reading the data from the one of thethird page and the fourth page, of the second set of pages, selected inresponse to the status; and responsive to receiving a fourth commandsequence, writing data to the one of the third page and the fourth page,of the second set of pages, selected in response to the status.
 14. Thememory device of claim 1, wherein the first set of pages furtherincludes a third page, and wherein the operation further includes:responsive to receiving the first command sequence, causing the addressdecoder to map the read command address to one of the first page in thefirst bank, the second page in the second bank and the third pageselected in response to the status; and responsive to receiving thesecond command sequence, causing the address decoder to map the writecommand address to one of the first page in the first bank, the secondpage in the second bank and the third page selected in response to thestatus.
 15. The memory device of claim 14, wherein the third page is ina third bank of the memory.
 16. A method of operating a memory deviceincluding a memory having pages and banks, the method comprising:configuring a first set of pages of the memory to include a first pagein a first bank and a second page in a second bank; mapping receivedcommand addresses to physical addresses of the pages and the banks ofthe memory; maintaining a status indicating a most recently written pageof the first set of pages; decoding received command sequences thatcomprise the command addresses; executing operations identified in thecommand sequences; and implementing an operation including: responsiveto receiving a first command sequence including a read command addressthat is pre-configured for reading data from the first set of pages, (i)selecting one of the first page in the first bank and the second page inthe second bank in response to the maintained status and (ii) mappingthe read command address to the selected one of the first page in thefirst bank and the second page in the second bank; and responsive toreceiving a second command sequence including a write command addressthat is pre-configured for writing to the first set of pages, (i)selecting one of the first page in the first bank and the second page inthe second bank in response to the maintained status and (ii) mappingthe write command address to the selected one of the first page in thefirst bank and the second page in the second bank.
 17. The method ofclaim 16, wherein the operation further includes: responsive toreceiving the first command sequence, reading the data from the one ofthe first page and the second page, of the first set of pages, selectedin response to the status; and responsive to receiving the secondcommand sequence during the reading of the data, writing data to the oneof the first page and the second page, of the first set of pages,selected in response to the status.
 18. The method of claim 17, whereinthe selected one of the first page and the second page, from which thedata is read, is one of the first page and the second page indicated bythe status as being the most recently written page.
 19. The method ofclaim 17, wherein the operation further includes, after completion ofthe writing, updating the status to indicate the one of the first pageand the second page, to which the data was written, as the most recentlywritten page of the first set of pages.
 20. A method of manufacturing amemory device including: providing a memory configured with pages, thepages including a first set of pages including a first page in a firstbank and a second page in a second bank; providing and configuring anaddress decoder to map received command addresses to physical addressesof pages and banks of the memory; and providing control circuitryconfigured to maintain a status indicating a most recently written pageof the first set of pages, to decode received command sequences thatcomprise the command addresses, to execute operations identified in thecommand sequences, and to implement an operation including: responsiveto receiving a first command sequence including a read command addressthat is pre-configured for reading data from the first set of pages, (i)selecting one of the first page in the first bank and the second page inthe second bank in response to the maintained status and (ii) causingthe address decoder to map the read command address to the selected oneof the first page in the first bank and the second page in the secondbank; and responsive to receiving a second command sequence including awrite command address that is pre-configured for writing to the firstset of pages, (i) selecting one of the first page in the first bank andthe second page in the second bank in response to the maintained statusand (ii) causing the address decoder to map the write command address tothe selected one of the first page in the first bank and the second pagein the second bank.